From d07e5fcf3fdb59fea67a644fad6d8dd38672124c Mon Sep 17 00:00:00 2001
From: Uwe Rathmann <Uwe.Rathmann@tigertal.de>
Date: Wed, 26 May 2021 13:06:50 +0200
Subject: [PATCH] qskFuzzyFllor/qskFuzzyCeil added

---
 src/common/QskFunctions.cpp | 25 +++++++++++++++++++++++++
 src/common/QskFunctions.h   | 19 +++++++++++--------
 2 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/src/common/QskFunctions.cpp b/src/common/QskFunctions.cpp
index 6917b108..8187adf7 100644
--- a/src/common/QskFunctions.cpp
+++ b/src/common/QskFunctions.cpp
@@ -22,6 +22,8 @@ QSK_QT_PRIVATE_END
 #include <qpa/qplatformintegration.h>
 #include <qpa/qplatformscreen.h>
 
+#include <cmath>
+
 template< class Rect, class Value >
 static inline Rect qskAlignedRect( const Rect& outerRect,
     Value width, Value height, Qt::Alignment alignment )
@@ -193,3 +195,26 @@ QRect qskPlatformScreenGeometry( const QScreen* screen )
 
     return screen->handle()->geometry();
 }
+
+/*
+    Due to the nature of floating point arithmetic
+    we might floor a value, that is already "aligned"
+    F.e static_cast< int >( 0.29 / 0.01 ) -> 28
+ */
+qreal qskFuzzyFloor( qreal value, qreal stepSize )
+{
+    qreal v = std::floor( value / stepSize ) * stepSize;
+    if ( qFuzzyCompare( value - v, stepSize ) )
+        v = value;
+
+    return v;
+}
+
+qreal qskFuzzyCeil( qreal value, qreal stepSize )
+{
+    qreal v = std::ceil( value / stepSize ) * stepSize;
+    if ( qFuzzyCompare( v - value, stepSize ) )
+        v = value;
+
+    return v;
+}
diff --git a/src/common/QskFunctions.h b/src/common/QskFunctions.h
index ea8ba764..b8a95b1d 100644
--- a/src/common/QskFunctions.h
+++ b/src/common/QskFunctions.h
@@ -36,6 +36,15 @@ QSK_EXPORT QRectF qskValidOrEmptyInnerRect(
 QSK_EXPORT qreal qskHorizontalAdvance( const QFont&, const QString& );
 QSK_EXPORT qreal qskHorizontalAdvance( const QFontMetricsF&, const QString& );
 
+inline QMarginsF qskMargins( const QRectF& rect, const QRectF& innerRect )
+{
+    return QMarginsF(
+        innerRect.left() - rect.left(),
+        innerRect.top() - rect.top(),
+        rect.right() - innerRect.right(),
+        rect.bottom() - innerRect.bottom() );
+}
+
 inline bool qskFuzzyCompare( qreal value1, qreal value2 )
 {
     if ( qFuzzyIsNull( value1 ) )
@@ -47,13 +56,7 @@ inline bool qskFuzzyCompare( qreal value1, qreal value2 )
     return qFuzzyCompare( value1, value2 );
 }
 
-inline QMarginsF qskMargins( const QRectF& rect, const QRectF& innerRect )
-{
-    return QMarginsF(
-        innerRect.left() - rect.left(),
-        innerRect.top() - rect.top(),
-        rect.right() - innerRect.right(),
-        rect.bottom() - innerRect.bottom() );
-}
+QSK_EXPORT qreal qskFuzzyFloor( qreal value, qreal stepSize );
+QSK_EXPORT qreal qskFuzzyCeil( qreal value, qreal stepSize );
 
 #endif